I'm sure Obama and congress have all taken the threat seriously. But that doesn't mean they're going to talk about it a lot in the news. It's often easiest for the CIA and NSA to investigate and assess threats when there's not a lot of attention around them.
The UN, US, China, Japan & others are all very concerned. But if they show too much fear it gives NK more power to think they can do anything they like. The downfall of dictators is underestimating their opponents. Their arrogance & decisions are driven by ego vs. common sense, forethought & empathy for others. Eventually NK w/ overstep bounds & be bombed. Probably their nuclear sites. Unfortunately innocent people will die. But it's quicker than starvation at the hands of your own gov't, right? (Sarcasm.)
One, there is no indication that President Obama is not taking these threats seriously. Just because he is not declaring war and sending troops into Korea does not mean he doesn't care about America's security. Two, North Korea has made these threats many times and never acts or carries them out. Three, we would know if North Korea is mobilzing their armies, so we would know of an attack three to four days in advanced. Four, North Korea does not have a missile strong enough to carry a nuclear payload or reach the United States. Obama is taking this threat to heart and is aware of the situation.
"We are on the verge of a global transformation. All we need is the right major crisis and the nations will accept the New World Order." - David Rockefeller
Perhaps the government is hoping that N. Korea will give us this "right major crises." Or, they are glad we were threatened and the government will nuke us themselves and make it look like N. Korea did it. All we need is a crises that will cripple the U.S., and we can have this "wonderful" New World Order.